To resolve the error, one workaround is to use the “Initialize Function” block to assign a string value to the “Data Store Memory” block. This works because the “Initialize Function” block is a preconfigured Subsystem block that executes during a model initialization event.
Kindly refer to the following images to understand how to use the "Initialize Function" block.
For more information on “Initialize Function” block kindly refer following MathWorks Documentation.
I hope this will be helpful.
